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The Role Of The Thermocouple In A Residential Furnace

Despite being a relatively simple home appliance, the furnace remains a source of mystery to many homeowners. Unfortunately, this often leads to the need for furnace repairs that could have been avoided through some basic education. If you would like to learn more about the inner workings of your furnace, read on. This article will discuss the job played by the component known as the thermocouple.

The Basic Picture

The thermocouple lies at the heart of your furnace’s built-in safety system. Its job is quite simple: cutting off the flow of gas in the event that the pilot light happens to go out. If the gas were allowed to keep flowing, it would soon reach poisonous–and potentially explosive–levels inside of your house.

Mechanical Explanation

In order to do its job, the thermocouple uses the heat from the pilot light. This heat causes two strips of metal located near the tip of the thermocouple to become super-heated, expand, and generate an electrical charge. This charge is routed to the gas valve. As long as the electrical impulse remains constant, the pilot valve remains open and the gas continues flowing.

In the event that the pilot light goes out, however, the strips of metal in the thermocouple cease to produce their electrical impulse. This causes the gas valve to close, thus choking off the flow of gas. Problems sometime ensue when the thermocouple ceases to produce its charge even though the pilot light is still on. This problem can often be addressed by physically reorienting the thermocouple so that it is closer to the flame. If that doesn’t work, it may be necessary to install a new thermocouple.

If you believe that your thermocouple may be experiencing problems, please don’t hesitate to contact us.